Acoustic device for detecting moving particles in a fluid



R. A. CORDA Sept. 19, 1967 ACOUSTIC DEVICE FOR DETECTING MOVING PARTICLES IN A FLUID Filed April 10, 1964 Jade W JPaZ'erZA 507-Za H l l'i i i Mf a United States Patent ()fifice 3,343,126 Patented Sept. 19, 1967 3,343,126 ACOUSTIC DEVICE FOR DETECTING MOVING PARTICLES IN A FLUID Robert A. Corda, Leominster, Mass, assignor of one-third to Everett H. Duchesneau and one-third to Ernest L.

Duchesneau, both of Leominster, Mass., jointly Filed Apr. 10, 1964, Ser. No. 358,693 3 Claims. (Cl. 340-148) This invention relates to a signaling device which is operated by sound energy and involves the use of a microphone to pick up the sound, an amplifier for the usual purpose connected with the microphone, and an amplifier operated switching device such as a solenoid with an electric switch connected to it for either closing a circuit to a signaling device which may be either visual or audible, or on the other hand for opening a circuit turning a motor olf, depending upon the application to which the sound operated alarm signal is to be applied.

A further object of the invention resides in the provision of a sounding bar which is a free-ended metal bar having a support that leaves the free-end and being of a nature that transfers suflicient sound waves or vibrations to a microphone attached thereto when the sounding bar is struck by a solid object, the microphone in turn being connected as described above through an amplifier to a signal system.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings in which:

FIG. 1 is a view which is partly diagrammatic illustrating the invention used with a normally closed switch;

FIG. 2 is a fragmentary view, looking in the direction of arrow 2 in FIG. 1, and

FIG. 3 shows a part of the electric circuit of FIG. 1 utilizing a normally open switch.

To illustrate the invention, there is here provided a container which is shown in dotted lines, this container being indicated by the numeral and actually forming no essential part of the invention. However upon a wall of this container, or on some other support, there is mounted the sounding bar generally indicated at 12 which is an elongated metal bar having in this case a portion 14 which extends upwardly bending at 16 over the upper edge 18 of the container 10 and then down into the container as indicated at 20. The free end 22 of this bar is free of any part of the container or anything else and especially terminates short of the bottom of the container which is indicated at 24.

Any desired or convenient means may be utilized for mounting the portion or arm 14 of the sounding bar at its lower end as for instance a two-part metal clamping bracket generally indicated at 26, having fasteners extending therethrough into any kind of support such as the wall of the container 10. The principal function of the bracket 26 is to support the sounding bar in operative position but not to interfere in any way with its sounding properties or vibrations.

A microphone is indicated at 28. This microphone can be of any form and can be attached by any kind of fasteners or brackets to the arm 14 of the sounding bar, or it can be built in if this should be desirable or convenient. This microphone is directly mounted on the bar no matter how it is held thereto and is connected to an amplifier 30. The amplifier amplifies the signal received from the microphone and passes it to a solenoid or other kind of relay 32 which in this case controls a normally closed switch 34. The switch 34 controls a circuit 36 in which there is a motor 38 and whenever the microphone receives a signal from the sounding bar, the switch at 34 will be opened and shut off the motor.

This of course can be varied to use the normally opened switch 40 shown in FIG. 3 so that the solenoid will close the same, energizing the circuit 42 and operating the signal 44 which can be visual or audible.

One of the uses to which the present invention can be put is to place the arm 20 of the sounding bar in a stream of relatively fluid material so that when a foreign object, i.e., an unwanted piece of solid material, strikes it, the sound or vibration is passed to the microphone 28 which then operates either the circuit of FIG. 1 or of FIG. 3, depending upon which is used, in the way described. The motor 38 would then be used to stop a pump which is creating the stream, or it can be used in any other way, or the signal can be used to alert an operator for whatever purpose may be desired, as to the presence of a foreign object.

A specific application of the present invention resides in the preparation for instance of comestibles for further processing. Thus if there is some food product which is being processed in the container 10 and a foreign object such as a piece of metal or a stone should unfortunately be present, the same will strike the arm 20, cansing the operation of the device as aforesaid. The operator can then remove the foreign object, and re-start the operation.

In order to make the operation even more eifective, the sounding arm 12 can be duplicated at the opposite side of the container 10 as indicated in FIG. 1 and the microphone thereof can also be connected by a separate jack into the amplifier 30, so that either sounding bar will then cause operation of the device in the way stated.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

1. A device for detecting the presence of unwanted objects in a fluent material comprising the combination of a container adapted to receive relatively fluid material in motion therein, a sounding bar, said sounding bar including means supporting the same with a free end extending into the container in position in the fluent material a microphone on to said sounding bar, transmitting energy derived therefrom upon contact of an unwanted object therein, an amplifier receiving signals from the microphone and amplifying the same, an electrically operated switch operated from the amplifier upon signal from the microphone, a circuit, the switch controllin the circuit, and anappliance in said circuit controlled by the switch upon receipt of an impulse from the amplifier under control of the microphone.

2. The combination of claim 1 wherein the switch is normally open.

3. The combination of claim 1 wherein the switch is normally closed.

References Cited UNITED STATES PATENTS 1,689,121 10/1928 Ferdon 340 -148 2,419,099 4/1947 Wall 340-148 NEIL C. READ, Primary Examiner.

I-I. PITTS, Assistant Examiner. 

1. A DEVICE FOR DETECTING THE PRESENCE OF UNWANTED OBJECTS IN A FLUENT MATERIAL COMPRISING THE COMBINATION OF A CONTAINER ADAPTED TO RECEIVE RELATIVELY FLUID MATERIAL IN MOTION THEREIN, A SOUNDING BAR, SAID SOUNDING BAR INCLUDING MEANS SUPPORTING THE SAME WITH A FREE END EXTENDING INTO THE CONTAINER IN POSITION IN THE FLUENT MATERIAL A MICROPHONE ON TO SAID SOUNDING BAR, TRANSMITTING ENERGY DERIVED THEREFORM UPON CONTACT OF AN UNWANTED OBJECT THEREIN, AN AMPLIFIER RECEIVING SIGNALS FROM THE MICROPHONE AND AMPLIFYING THE SAME, AN ELECTRICALLY OPERATED SWITCH OPERATED FROM THE AMPLIFIER UPON SIGNAL FROM THE MICROPHONE, A CIRCUIT, THE SWITCH CONTROLLING THE CIRCUIT, AND AN APPLIANCE IN SAID CIRCUIT CONTROLLED BY THE SWITCH UPON RECEIPT OF AN IMPULSE FROM THE AMPLIFIER UNDER CONTROL OF THE MICROPHONE. 